I haven't seen much of Brett Cecil, but the following video gives us a glimpse of his mechanics, at least during a bullpen session. It's not much to go by, and without breaking the video down by frame it's hard to really critique his arm and shoulder motion. However, Cecil has a nice fluid motion, and I really like his transition from leg kick to plant, and then follow-through. I've seen a lot of young pitchers that have a lot of wasted motion in their move to the plate, but Cecil looks very efficient.
There's also a decent forum discussion at TwoPlus Two Poker I found covering the topic of Cecil's mechanics if you're interested, although I couldn't get the animated images to work.